New Strain Of Whitefly Poses Grave Menace To Crops

November 10, 1991|The New York Times

EL CENTRO, Calif. -- In 30 years of farming the Imperial Valley, Ben C. Abatti and his brother, Tony, have fought every kind of natural and economic foe, but nothing like the poinsettia sweetpotato whitefly.

Abatti has just finished plowing under his melon crop, turned into pitiful shriveled and rotted fruits by the tiny but voracious creature.

And farm experts say the misfortune by farmers like Abatti will soon translate into shortages and higher prices in markets as far away as New York in the Thanksgiving and Christmas holidays.

Already, farmers have plowed under about 95 percent of the fall crop of cantaloupes and honeydew melons in Southern California and adjoining areas of western Arizona and northern Mexico. The region supplies the bulk of produce to the nation in the winter.

Fears are mounting that the winter crop of lettuce, broccoli, cauliflower and other vegetables will also be devastated. The plants are stunted, and farmers plan to delay the harvest, which usually begins in early December.

``This is the first time we`ve seen a pest that will eat just about anything,`` said Richard C. Weddle, an entomologist with the Imperial County Agricultural Commission. ``This is a first-rate natural disaster.``

The culprit is a potent new strain of the sweetpotato whitefly, an old foe of farmers. The new strain has been dubbed the poinsettia because it first appeared on poinsettia plants in Florida in 1986.

It lays about twice as many eggs as earlier strains and eats five times as much, said Thomas M. Perring, professor of entomology at the University of California at Riverside.

The pest colonizes the undersides of leaves and sucks out their juices. It has proved resistant to all chemical pesticides.

Experts are furiously searching for natural predators but for now have been reduced to trying to halt the fly`s spread by having farmers quickly plow their infested fields and sow the few crops it does not attack to interrupt the creature`s life cycle.

The most immediate effect on consumers will be a shortage of melons. The wholesale price of a carton of cantaloupes in the Imperial Valley has risen from about $6 to about $20, said Arthur M. Verissimo, chief of the market news branch at the California Department of Food and Agriculture.

This has more than doubled retail supermarket prices in parts of the country. The outlook for the winter vegetables is unclear, Verissimo said, but prices of lettuce and broccoli are expected to soar, too.

But Keith Mayberry, a farm adviser at the University of California Cooperative Extension in Holtville, said the advent of cold weather could bring at least some improvement because the insects are sensitive to cold.